waze.tools was, indeed, hosted on a server in OVH's Strasbourg data centre, which caught fire a little over a week ago.
From following the story, I'm aware that some sections of the data centre that survived the fire are due to come back online next week. Whether that includes the waze.tools server; whether it had any backups if it's been lost - I don't have answers to those questions.
The Global Champ who hosts waze.tools is providing the service to the community for free. I'm aware that his business is also in IT, so I suspect he has lost far more important servers than the freebie he's letting us use.
I've therefore not asked for any updates; I expect he has bigger worries than us.
I would give it another week or two, before worrying about the long-term fate of forum signatures.